#include<vector>
#include<iostream>
using namespace::std;

namespace dt
{
    template<class T>
    struct less
    {
        bool operator()(const T& left, const T& right)
        {
            return left < right;
        }
    };

    template<class T>//
    struct greater
    {
        bool operator()(const T& left, const T& right)
        {
            return left > right;
        }
    }; 

    template<class T, class Container = vector<T>, class Compare = less<T>>
    class priority_queue
    {
    public:
        priority_queue()
        {}

        void adjust_down(int parent)
        {
            Compare com;
            size_t child = parent * 2 + 1;
            while (child < _con.size())
            {
                if (child + 1 <+_con.size() && com(_con[child], _con[child + 1]))
                {
                    ++child;
                }

                if (com(_con[parent], _con[child]))
                {
                    swap(_con[child], _con[parent]);
                    parent = child;
                    child = parent * 2 + 1;
                }

                else 
                {
                    break;
                }
            }
        }

        void push(const T& x)
        {
            _con.push_back(x);
            adjust_up(_con.size() - 1);
        }

        void pop()
        {
            swap(_con[0], _con[_con.size()-1]);
			_con.pop_back();
			adjust_down(0);
        }

        const T& top()
		{
			return _con[0];
		}

		bool empty()
		{
			return _con.empty();
		}

		size_t size()
		{
			return _con.size();
		}

        template<class InputIterator>
        priority_queue(InputIterator first, Inputiterator last)
            :_con(first, last)
        {
            for (int i = (_con.size()-2) / 2; i >= 0; --i)
            {
                adjust_down(i);
            }
        }

    private:
        Container _con;
    };
}